Federal Reserve Bank of Dallas. "[Savings Bonds], Circular No. 72-41," District Notices (Federal Reserve Bank of Dallas) (February 28, 1972). https://fraser.stlouisfed.org/scribd/?item_id=544714&filepath=/files/docs/historical/frbdal/circulars/frbdallas_circ_19720228_no72-041.pdf&start_page=1, accessed on September 24, 2017.
Redesign Series E and H; 4th Amendment to Treasury Department Circular No. 530; 1st and 2nd Supplements to Treasury Department Circular No. 653